Improvement in valve-gears for steam-engines



Q52.; JOHN c. MACDQNALD.

Improvement in Valve Gear for Stam Engines.

.Patented Decac26, 1871.

www1-:sass: :NVENTDR' i inde r.

Uivrrnn l Srnfrns JOHN C. MACDONALD, OF ST. LOUIS, MISSOURI.

IMPROVEMENT' IN4 VALVE-SEARS FOR STEAM-ENGINES.

Specication forming part of Letters Patent No. 122,269, dated December26, 1871.

To all whom 'it may concern.-

Be it known that I, JonN C. MACDONALD, of

St. Louis, in the county of St. Louis and State oi' Missouri, haveinadcxcertain new and useful Improvements in Valve-Gear forSteam-Cylinders; and I do hereby declare that the following is a fulland true description thereof, reference being had to the accompanyingdrawing and to the letters of reference marked thereon.

The object oi' the improvements here presented is to dispense withvalve-rods and connecting attachments ordinarilynsed to operatepiston-rods and pistons oi' steam-cylinders, and to gain the y requiredreciprocating motion for the piston byr the direct action oi steampressure or power.

To achieve said object the nature of this invention relates: First, tothe peculiar arrangement and construction of auxiliary cylinders andtheir reverse acting stops and slidevalves, in combination with the maincylinder oi'steam-engines.

\ Secondly, to the arrangement of inductive and Y exhaust steam-passagesand ports, by which the steam-power shall operate the valves in theauxiliary cylinders at regular periods to impart the y requiredreciprocating motion to cylinder-pisy Fig. 5 lis a transverse section atline m4 m4.

A is the main cylinder. A1 is the piston-cyl- A2 the piston=rod asordinary. The main cylinder A is provided with main steam-ports a, al a?a, the said ports a al communicating from i vcylinder steani-space withthe steam-chest A3,

the said ports c2 a?, however, being arranged horizontally and leadingto the exhaust-pipe. The

steam is fed into steam-chest A3 through side v port a", (see Fig. 5,)the exhaust escaping ont of main exhaust a5, Figs. l and2. WVithin thesteamchest o n top cylinder A are the auxiliary cylinders, constructed,arranged, and provided with the valve-gear as follows: The slide-valvecylinder B is provided with proper piston B1. In order to form therequired steam-tight joints for said piston the heads B2 of cylinder Bare cored with projecting cylindrical faces Within and Without saidcylinder. (See Figs. l and 2.) .The joint thus formed obviatessteam-jacketing, also is more durable and reliable. At the ends of thepiston-rod of piston Bl are valve-heads C C, these being adjustablyattached to said rod ends by proper set-screws. Further, the valve-headsG O are properly mortised to receive the bii'urcated extensions of thereverse acting slide-valves D D. The body of said valves is formedD-shaped, being cored hollowr to carry the exhaust steam from either endof cylinder alternately to main exhaust. The arrangement, therefore,ofthe auX- iliary cylinder B and its reverse slide-valves D D is suchthat said valves shall open and close the main inductive and exhaustports a al a? a3, as illustrated in Figs. l and 2. Also, forming part ofthe cylinder B is the further auxiliary cylinder E, cored with properinner shoulders to limit the stroke of its stopyalve E,Which isconstructed and arranged as follows: The said stopvaive E consists ofcylindrical section FF' formed ywith thc respective valve orpiston-heads ffl.

(See Figs. 3 and 4.) In order to unite said sectional Valve E Within thecylinder E, the sectional part F has at its `inner end a stationaryturirbolt, this being iitted to lock in a proper slot in the contiguousarranged sectional part F', as indicated in Figs. 3 and 4. Thecylindrical stop-valve E', when arranged to abut against the shoulderswithin the auxiliary cylinder E, forms steam-spaces or chambers G G',(see Figs. 3 anden) in which steam is admitted from the main cylinder,as Will hereinafter appear. In order to guide in its slide motion thestop-valve E lthe same is provided ou top with a groove in whichset-screwsfZ are fitted to engage; all lateral or irregular motiononpart of said stop-valve is thus prevented. The duplicate arrangementof steam passages and ports to admit steam from the main cylinder tooperate the valve-gear, loe-A fore described, is as follows: Thecylindrical stopvalve E' is operated by steam from cylinder A, passingthrough ports b Z2',- these ports are positioned at the outer ends ofsaid cylinder to communicate by diagonal passages with the steamchambers(5r G of the auxiliary cylinder E, as clearly shown in Figs. 3 and 4.Further, there are similarly arranged the ports c c1 to communi# rrrcn.y

meteen l cate'from' the main cylinder with D- shaped ports from maincylinder passing through ports c 01 c2 c3' c4 c5 into slide-valvecylinder B in an alternate manner, operates its piston` B1 to in ake thereverse stroke required. Also, it will be noticed that by thearrangements of all said parts the cylindrical stop-valve E is operatedy alternately'by steam-y power froni main cylinder to admit, exhaust,and cut-off at proper periods the stearnlfrom the rer verse actingslidevalves D The exhaust from the top c-ylinderB is passed through theports c1 c5, into D-sh'aped ports c2 c3 4of the valve E', from thenceout of central exhaust-port c, shownA in Figs. 2, 3, and 4, which leadsto main exhaust or escape-pipe. The exhaustfrom'the steam-chambers Gr Gof the cylinder E returns and `escapes with exhaust of main cylinderAA.-The direct action of steam passing through the passages arranged `asdescribed and shown is as follows: Supposing the main port a opened tolive steam, the ports a3 a1 are opened to exhaust. The piston A1 havingnearly finished its; return stroke, steam -port c1 is uncovered,admitting steam through said port into D-s'haped port c3, from thencethrough p ort or passage c5 into the slidevalve cylinder B, operatingits piston B1to the left, which reverses the slide-valves DD. to openthe main port a1 to live steam Land the main ports Y a a? to exhaust,(Figs. l and 3;) at the same time the exhaust of cylinder B is escapingthrough port c1 into D-sh'aped port c2, from thence through centralexhaust-port c6 outof the exhaust-pipe.

The piston A1, now ready to commence its for-A ward stroke, uncoversport b admitting steam into the steam-chamber G', (of cylinder E,)reversing it-slstop-valveE to close port c1 to live steam, open ports c5tG to exhaust, also opening port c to receive live steam as soon asthepiston has passed said port c in its forward stroke. s Immediately,thereibre, as the reverse stroke of the piston occurs, simultaneouslyoccurs' the reverse stroke of the reverse-acting valves, which openexhaustports, allowing escape of the exhaust from one My saidimprovedvalve arrangements are readilyrepaired, also are not liable to disorder,breakage, or leakage of any of its parts, utilizing the full power ofsteam, their operation being With less friction and greater power aswell as with regularity, precision, and certainty.

Having thus fully described my said improve- 1. The cylindricalstop-valve E formed in sections F F having heads f f1, D-shaped ports c2c3, when arranged to operate asu and for the purpose set forth.

2. `The arrangement of'auxiliary cylinders B and E, piston B1, doublevalve-heads' C, reverse slide-valves I) D, cylindrical ystop-valve E',constructed to operate in combination vwith main cylindcr A,substantially as and for the purpose set forth.

3. The' arrangement of steam-passages or ports b b', steam-chambers GG', in ycombination with auxiliary cylinder E an d cylinder A,substantially as and for the purpose set forth.

4. The arrangement of inductive and exhaust ports c c1, D-ports' cz'cs,ports and passages c4115 c, in combination with cylinders E, cylindriealstop-valves E', and main cylinder A, substantially as and for thepurpose set forth.

5. The auxiliary cylinders BE, valves E' D D,

steam-ports c c1 b b c2' c3 c4 c5 c, arranged in coinbination withsteam-chest A3, cylinder Ahaving. main ports a a1 a2 a3, piston A1, whenall said parts are constructed and arranged to Voperate as and for thepurpose set forth.

In testimony of said invention I have hereunto setmyhand.

I JOHN C. MACDONALD. in presence of WILLIAM W. HERTHEL,

ROBERT BURNS. (152) It will be noticed that, as the action of i

